A typical EDLC comprises at least one electrode made of a nanoporous carbon material. The second electrode can be made either of a similar nanoporous carbon (as in so called symmetrical EDLC devices) or of a different material taken from battery technology (as in so called asymmetrical or hybrid devices.) In either case the energy density stored in a typical EDLC device is less than that stored in a typical Pb/acid or Li-ion battery. On the other hand, one of key advantages of EDLC as compared to any other type of batteries is their low internal resistance, resulting in high power density and high efficiency. Among several contributors to the total internal resistance of EDLC, the resistance of electrolyte in the porous electrode matrix is the most significant.
Therefore, when selecting nanoporous carbons for EDLC electrodes, the electrolyte mobility in the porous electrodes, in particular different mobility of anions and cations, which influences the resistance of positive and negative electrodes, respectively, should be taken into consideration.
Accordingly, there is a need for developing a method for selecting nanoporous carbon materials capable of providing high mobility of electrolyte ions in their porous matrices and, correspondingly, low internal resistance of a EDLC device utilizing the selected carbons as electrode materials.